Spontaneous excitation of an accelerated hydrogen atom coupled with electromagnetic vacuum fluctuations

Abstract

We consider a multilevel hydrogen atom in interaction with the quantum electromagnetic field and separately calculate the contributions of the vacuum fluctuation and radiation reaction to the rate of change of the mean atomic energy of the atom for uniform acceleration. It is found that the acceleration disturbs the vacuum fluctuations in such a way that the delicate balance between the contributions of vacuum fluctuation and radiation reaction that exists for inertial atoms is broken, so that the transitions to higher-lying states from ground state are possible even in vacuum. In contrast to the case of an atom interacting with a scalar field, the contributions of both electromagnetic vacuum fluctuations and radiation reaction to the spontaneous emission rate are affected by the acceleration, and furthermore the contribution of the vacuum fluctuations contains a non-thermal acceleration-dependent correction, which is possibly observable.

Spontaneous absorption of an accelerated hydrogen atom near a conducting plane in vacuum

“…(48) with that of the unbounded Minkowski space [25] shows that, the boundary-dependent contribution is in fact a "nonthermal" correction proportional to the oscillating function f xx (ω bd , z, a). With the help of the following equations…”

“…Therefore, the presence of a plane boundary conspires to modify the vacuum fluctuations and radiation reaction in such a way that the delicate balance between the vacuum fluctuations and radiation reaction found in Ref. [25] in absence of boundaries remains and this ensures the stability of ground-state inertial atoms in vacuum with a conducting boundary. Second, if the atom is polarized in the parallel direction, then, as the atom is placed closer and closer to the boundary (z → 0), the rate of change of the atomic energy vanishes since f x (z, ω bd ) and f y (z, ω bd ) approach zero.…”

“…[8], where non-thermal corrections to the energy shifts were found in addition to the usual thermal ones associated with the temperature T = a/2π. Recently, the spontaneous excitation rate of an accelerated atom in the same system has been studied [25]. It has been found that both the effects of vacuum fluctuations and radiation reaction on the atom are changed by the acceleration.…”

“…However, one may wonder what happens to the spontaneous emission of accelerated multi-level atoms in interaction with quantized electromagnetic fields found in Ref. [25], when the vacuum fluctuations are further modified by the presence of boundaries. This is what we plan to address in the present paper; we will calculate the effects of modified vacuum fluctuations and radiation reaction due to the presence of a conducting plane boundary upon the spontaneous excitation of both an inertial and a uniformly accelerated multi-level atom interacting with a quantized electromagnetic field in the multipolar coupling scheme.…”

“…[7] and generalized in Ref. [24,25] to the case of a multi-level atom interacting with a quantized electromagnetic field in the multipolar coupling scheme, then apply it to the case of an inertial atom in Sec. III and to the case of an accelerated atom in Sec.…”